Drag Racing Depends & Powertrain Pampers: Ballistic Engine Diapers

Motorsports enthusiasts sometimes don’t realize that behind the glamour of car and motorcycle racing we see on television there is an extensive support industry that makes everything from specialized dipsticks to complete racecars. Much of that industry is located in three locations around the globe. England’s so called Motorsports Valley is where 8 of the 11 F1 teams have their race shops within about an hour’s drive from the Silverstone track, in Northamptonshire, Oxfordshire and the South Midlands. About 45,000 people in the UK make their living from motorsports. In the U.S., the racing industry is primarily centered, not surprisingly, around Indianapolis, Indiana and Charlotte, North Carolina, home of the Indianapolis 500 and NASCAR, respectively. It should also come as no surprise that Indiana’s Purdue University and the University of North Carolina at Charlotte have both examined the economic impact of motorsports in their states. Purdue reports that more than 23,000 people are employed directly by the motorsports industry in Indiana which in turn are responsible for another 423,000 indirect jobs. A decade ago UNC Charlotte found that motorsports then contributed $5 billion to the North Carolina economy.

Every year in December there is a big two day trade show in Indianapolis that was originally put on by Performance Racing Industry magazine. The PRI show, which draws thousands of racing professionals and is not open to the public, is now owned by the promoters of the SEMA show in Vegas. Dave Szerlag, who owns D&M Motorsport Promotions in Brighton, Michigan, and his business associate Luke Bogacki, realized that Indy and Charlotte aren’t the only areas in the country that have a critical mass of companies devoted to performance and racing cars, so they decided to organize the first Motor City Hot Rod & Racing Expo, held outside Detroit in Novi. Based on the fact that 140 vendors, from Michigan and around the country, bought up all 65,000 square feet of available display space, and the fact that every vendor that I spoke to said they were happy with the business they did at the show, I’d say that the inaugural event was as success. Szerlag and Bogacki told me they’re already planning next year’s show.

One of those vendors was J&J Performance of Shreve, Ohio and the main reason why I stopped by their booth was because the words “Engine Diapers” on their sign caught my eye. When a drag racing engine breaks, the term “grenading” is appropriate. Hard metal parts start flying and connecting rods or other components will simply break holes into the side of the crankcase or down through the sump as they continue on their vectors.

Why they call it a “thrown” rod.

Considering the kind of damage that can happen when the engine in a production street car throws a rod, you can imagine how violent it is when a racing engine putting out more than a thousand horsepower (and in the case of top fuel engines running on nitromethane, several thousand horsepower) starts to break. That creates a safety problem since those flying parts can be in the proximity of the driver and the leaking oil can cause a fire or create traction problems for both drag racing competitors. It also annoys track owners when drag racers’ engine parts and oil get dumped on their tracks. Hence ballistic engine diapers are now being required by the NHRA and IHRA for some racing classes.

When a top fuel engine blows up, it really blows up.

J&J is one of a number of firms that make engine diapers. The name is appropriate as an engine diaper wraps around the engine’s bottom end, keeping any leaking oil or stray parts contained. The diaper is secured to the engine with straps, not safety pins (nor for you modern parents who don’t know how to use cloth diapers, adhesive strips). J&J offers two styles, one of woven Kevlar aramid fabric and the other made of an outer skin of ballistic nylon with an inner core of thin ballistic armor. Other companies make similar soft sided engine diapers as well as more rigid units fabricated with carbon fiber. J&J’s rep told me that the styles are about equally effective and end up weighing about the same, so it’s really more of a personal preference thing.

Back when Formula One allowed purpose-built qualifying engines, some folks called them “hand-grenades”, built to put out massive amounts of power for a limited number of laps. Drag racing engines only need to last 1/4 mile, so they tend to be built very close to the edge of the performance envelope. At the highest echelons of drag racing, the engines are rebuilt after after run. Drag racing in particular is going to experience more blown engines than other kinds of racing, so it’s understandable that the drag racing community has embraced the idea of engine diapers. I’m just surprised that they haven’t caught on in other forms of car racing. One driver’s blown engine in a NASCAR race often leads to yellow flags, so the oil on the track can be cleaned up, if they’re lucky and that oil hasn’t already caused other drivers to spin. Many top level racing series mandate safety items like tethered wheels to reduce the chance of flying debris causing an accident. More widespread use of engine diapers in other forms of motorsports could mean safer racing for drivers and more exciting racing for fans, who don’t pay money to watch fast cars parade around the track behind the pace car.

Ronnie Schreiber edits Cars In Depth, a realistic perspective on cars & car culture and the original 3D car site. If you found this post worthwhile, you can get a parallax view at Cars In Depth. If the 3D thing freaks you out, don’t worry, all the photo and video players in use at the site have mono options. Thanks for reading – RJS